A mass damper or damper for short, damps vibrations in a vibrating system by having as the central active element a vibrating mass of its own, which vibrates opposite the vibration of the vibrating main object of the vibrating system. The vibrating mass of the damper may also be called countervibrating mass, because it vibrates in antiphase to the exciting vibration of the vibrating system. The countervibrating mass or damping mass forms, together with a damping spring, a physical pendulum, whose resonant frequency is set at a certain ratio to the vibration frequency of the vibrating system, which such vibration frequency is to be damped. The damper can perform great deflections at this resonant frequency and extract vibration energy from the vibrating structure to be damped for its own vibration motions. A mass damper is called “tuned mass damper” or “active mass damper or “harmonic absorber” in the English usage.
Mass dampers are frequently used when so-called “resonance catastrophes” are to be prevented in the vibrating system. A resonance catastrophe develops when the vibrating system has a resonant frequency and is induced to perform vibrations in the range of the resonant frequency. The vibration amplitudes may grow in this case to unacceptably high values or “build up.” As a consequence, disintegration of the vibrating system may occur. If the mass damper is tuned exactly to this resonant frequency of the vibrating system, very much vibration energy is extracted from the vibrating system in the range of the resonant frequency, as a result of which the vibration amplitudes can be significantly reduced. If the vibrating system has more than one critical resonant frequency, a plurality of differently tuned mass dampers must be correspondingly provided. The effort needed for this is comparatively great. Furthermore, the mass dampers may mutually hinder each other concerning their function due to their being connected to the vibrating system.